Group the stylesheet import lists by component stream

tailwind.css and components.css now hold one block per audit group, and the new
layout.css gathers the layout components, so the parallel rewrites of plan steps
35 and 36 each edit their own lines. .browser-lock is the lock that keeps those
streams to one browser at a time.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

workbench/resources/css/app.css

@@ -3,6 +3,7 @@
    `material` layers are declared first and sit below Tailwind's; tailwind.css brings the
    components still written for Tailwind, without declaring the tokens a second time. */
 @import '../../../resources/css/foundation.css';
+@import '../../../resources/css/layout.css';
 @import '../../../resources/css/components.css';
 @import 'tailwindcss' source(none);
 @import '../../../resources/css/tailwind.css';